It is an established fact that vitamin b12 aka cyanocobalamin is an important vitamin that is synthesized in nature by most micro organism and the only way animals or humans acquire it is by eating other animals, dietary foods. But it does not occur in fruits, or cereals. It's defiency is mostly associated with megaloblastic anaemia. It's role in the body is numerous e.g it functions as a cofactor in the enzyme methionine synthase, this enzyme is the one that help in the synthesis of methionine. It is indirectly involved in DNA synthesis.
The need to ensure that our diet contains vitamin b12 is of paramount importance.
Well said and pointed out facts and alternatives for the vegans @reddust